1. Field of the Invention
The present invention relates generally to a lift for moving a wheelchair over a stairway, and more particularly to, a wheelchair transfer mechanism for transferring a wheelchair over a stairway.
2. Description of Related Art
In the past, there have been mechanisms for transferring a person in a wheelchair over a stairway when that person is physically unable to move up or down the stairs. One such mechanism is disclosed in U.S. Pat. No. 3,749,202 to Puls which is directed to a stairway seatcar elevator. The stairway seat car elevator has a pair of guide rails mounted on one side of a staircase in vertically spaced parallel relation and a seatcar extending between the rails for guided movement along the stairway. A drive assembly for moving the seatcar includes a pulley mounted on the frame of the seatcar and a cable fixed at the top of the stairs which is passed around the pulley and back to a cable drum which is driven by a reversible motor.
Another mechanism is disclosed in U.S. Pat. No. 4,345,669 to Noall which discloses a wheelchair lift. The wheelchair lift includes a ramp pivotally attached to a wall of a staircase and a support platform mountable and dismountable from a carriage assembly which rides along the ramp.
One disadvantage of the above patent mechanisms is that the support platform does not extend completely across the staircase. This results in the person and wheelchair not being fully supported and/or being supported in a cantilever manner. Another disadvantage is that the mechanism may not facilitate the easy entry and exit of a wheelchair, requiring assistance by another person. A further disadvantage is that the support platform for supporting the wheelchair is not guided upon a pair of support rails on each side wall of the staircase.